1. Field of Use
This invention concerns a magnifier to facilitate inspecting work-pieces and parts. It relates especially to such a magnifier which also illuminates the work-piece or part being inspected.
2. Description of Prior Art (Background)
Conventional illuminating magnifiers have a housing which supports a large magnifying lens through which a worker may look to view a work-piece or part positioned below the lens. The housing also contains a light source to illuminate the lens's field of view. In the past, the light source often consisted of a fluorescent bulb encircling the lens and centered on the lens axis along with ballast powered by a 110 volt AC power source. Such bulbs are not environmentally friendly because they contain mercury and the presence of such high voltage in the magnifier is a potential hazard to the worker. Most importantly, the fluorescent light in the viewing area is not as bright and uniform as might be desired to enable a worker to carefully examine a work-piece in the viewing field of the lens.
More recently, magnifiers have been developed which utilize light-emitting diodes as the light source. However, invariably such diodes are of the bottle type with an integral lens which focuses the light from the diode to a point. Therefore, when pluralities of these diodes are arranged around the lens axis, the focused beams therefrom form a ring of hot spots at a fixed distance below the lens. Thus the amount of light incident on a work-piece or part being examined changes when the part is manipulated or the magnifier is moved up or down, thus increasing the chances of an examiner missing a defect in the part.
Other drawbacks of prior magnifiers are that they are not ergonomically friendly and do not give the worker enough control over the intensity and direction of the light incident on the work-piece being examined to enable a very careful examination of that part from all sides.